package y23.May;

public class Exam {
    public static void main(String[] args) {
        String str1 = "abcdAbCd";
        char[] arr1 = str1.toCharArray();
        int len1 = arr1.length;
        int i = 0;
        int j = 0;
        String s = "";
        for(;i < len1 - 1;i++){
            int count = 0;
            for(j=i+1;j < len1;j++){
                if(arr1[i] == arr1[j]){
                    count++;
                }
            }
            if(count != 1){
                s+=arr1[i];
            }
        }
        System.out.println(s);
    }
}
